1. Field of the Invention
The invention relates to communication networks, and specifically, to a communication hub that controls access to a communication network based on silence suppression.
2. Description of the Prior Art
Advanced communication networks are being developed to support a vast array of communication services. One example of an advanced communication network is a packet network. In a typical packet network, a communication hub located on a subscriber's premise and connected to one or multiple user devices exchanges communications with the network over a communication path. The communication path between the communication hub and the network typically includes a fixed bandwidth capacity agreed to between the customer and the service provider.
In one example of a call scenario using a packet network, a connection request is received in the communication hub from a user device. The communication hub suppresses, compresses, and packetizes the incoming digital signals from the user device for transmission to the network. At the network level, the network determines whether or not to allow the connection request using call admission control. Call admission control is the set of actions taken by the network during the call setup phase to accept or reject the connection request. For example, if the effective bandwidth for the connection request is greater than the provisioned bandwidth capacity purchased by the customer, the network will reject the call using call admission control. The effective bandwidth is the minimum bandwidth that needs to be allocated to meet the performance requirements for the currently active calls and the incoming connection request. If the connection request can be processed without violating the provisioned bandwidth, then the call is admitted.
To improve bandwidth efficiency the network uses silence suppression technology to fill silence periods in voice conversation packets with other call transmissions such as data, video, and imaging. A silence suppression gain factor is used to determine the required bandwidth for voice calls based on the silence suppression realized by filling the silence periods with other transmissions. The silence suppression gain factor is a constant based on a statistical calculation of the silence suppression realized for the large number of active voice calls present at any given time at the network level. The constant silence suppression gain factor is applied to incoming voice calls to determine the effective bandwidth for the currently active calls in conjunction with the incoming voice call.
To improve efficiency and reduce the demand on network resources, it is desired in the art to perform call admission control at the hub level and to use silence suppression technology to improve bandwidth efficiency between the communication hub and the network. Unfortunately, communication hubs cannot use a constant silence suppression gain factor. The constant silence suppression gain factor, while effective at the network level where large volumes of voice calls are present, is inaccurate at the hub level where only a small volume of voice calls may be present.